(1) Field of the Invention
The present invention relates to a suspension control apparatus for use in a vehicle.
(2) Description of Related Art
Performing an oscillation control of a vehicle body requires a lot of information, such as an up/down motion and a position (for example, pitch and roll) of the vehicle body, and up/down relative speeds between wheels and the vehicle body. If sensors dedicated for the respective data are mounted on the vehicle, the cost of the sensors is increased. Therefore, it is preferable to reduce the number of sensors as many as possible.
To reduce the number of sensors, for example, a value (such as an angular speed of a wheel) detected by a sensor mounted for another purpose than the oscillation control is utilized to calculate or estimate another value (for example, a relative speed between the wheel and the vehicle body) that can be used for the oscillation control. By this arrangement, a total of sensors on the whole vehicle can be reduced. Such a suspension control apparatus is disclosed in, for example, Japanese Patent Application Public Disclosure Hei 8-230433.
Although cutting down of the number of sensors is realized by the suspension control apparatus disclosed in Japanese Patent Application Public Disclosure Hei 8-230433, needs for reducing the number of sensors still continue to exist.